#define _CRT_SECURE_NO_WARNINGS 1

#include <iostream>
#include <vector>

using namespace std;

class Solution {
public:
    int singleNumber(vector<int>& nums) {
        int value = 0;
        for (auto e : v) { value ^= e; }
        return value;
    }
};

int main()
{
    return 0;
}